Visible emission in Sm3+and Tb3+doped phosphate glass excited by UV radiation

Abstract

ABSTRACT In the article analysis of UV abso rption and visible fluorescence of Sm 3+ and Tb 3+ ions doped phosphate glass with molar composition: 65P 2 O 5 + 8Al 2 O 3 + 10BaO + 17(Na 2 O + MgO + ZnO) have been investigated. As a result of optical pumping fabricated glass with radiation from a deuterium lamp four luminescence bands were observed near to the wavelength of 600 nm for Sm 3+ ions and 550 nm for Tb ions. It was found that larger energy gap between laser and ground levels leads to the strongest emission in the visible range in terbium doped glasses than in glasses doped with samarium ions. Both fabricated glasses are characterized by the ability to selectively detect the radiation in the UV range. Keywords : phosphate glass, Sm 3+ , Tb 3+ , UV excitation, visible emission, down-conversion 1. INTRODUCTION The needs of modern photonics impose on technologists and designers of optical fibers to search new glassy materials capable of propagation of electromagnetic radiation in a wide spectrum range. A choice of a matrix and optimization of its chemical, electrooptical and magnetooptical properties determines the range of applications [1-3]. Phosphate glasses are characterized by uniqu e properties, which are: high transmission in the range of UV-VIS-NIR, low refractive index (n = 1.5), dispersion, thermal stability, mechanical resistance and the ability to adopt high concentration of RE ions [4, 5]. It is high solubility of rare earth ions in multicomponent phosphate glasses that enables the construction of fiber amplifiers and fiber lasers [6-8]. On the other hand, the absorption edge in the range of short wavelengths of 200 nm enables to use them as active materials for the detection of UV radiation [9]. When considering the fabrication of such a sensor based on phosphate glasses the maximum phonon energy of the matrix, which is approx. 1000 cm